With the advent of cellular mobile telephones the need has arisen for antennas which mount on the window of a vehicle, thereby avoiding the need to drill holes in or otherwise modify the vehicle body. Preferably, such window-mounted antennas should offer a degree of performance comparable with body mounted antennas and should be economical to manufacture and easy to install.
One problem often encountered with such window-mounted antennas, which typically include an inside coupling unit connected to a coaxial feedline and an outside coupling unit on which a rod-shaped radiating element is mounted, is securing the outside unit to the outside surface of the window glass. The coupling unit must not only remain secure under adverse conditions of moisture, contamination, temperature and vibration, but also must be economical to manufacture and install.
The present invention provides a new and improved construction for an antenna coupling unit which offers both improved tolerance to adverse environmental conditions and improved ease of installation.